In an antiques shop in North London, there is a box. Inside the box is an ancient creature, seeping through into the world. It will show the Investigators the universe as it really is.

The Rending Box is the final Purist adventure for Trail of Cthulhu. The previous scenarios, The Dying of St Margaret's, The Watchers in the Sky and The Dance In The Blood have hinted about an immense, fecund creature, spawning beneath the soil of the Lake District.

In The Rending Box, the Investigators see that creature. Indeed, they may discover everything: the patterns behind the universe, the monsters older than time, the secrets that break your mind. And all they need to do is open a box.

This is the fourth and final installment of Graham Walmsley's Purist Adventure series, comprising of The Watchers in the Sky, The Dying of St Margaret's and The Dance in the Blood.